Heat 3-quart covered saucepan of salted water to boiling on high. Add couscous to boiling water and cook as label directs. Drain, rinse under cold water until cool, and drain again. To large bowl with lemon juice, whisk in 3 tablespoons oil and 1/4 teaspoon salt until blended. Add couscous, cucumber, onion, parsley, and mint. Mix well; set aside.

In 18 inch by 12 inch jelly-roll pan, combine asparagus, 1 teaspoon oil, 1/8 teaspoon salt, and 1/8 teaspoon freshly ground black pepper. Arrange in single layer, with bottoms of spears touching one long side of pan. Roast 5 to 7 minutes or until just tender. Meanwhile, in large bowl, toss shrimp with cayenne, remaining 1 teaspoon oil, and 1/8 teaspoon salt. In pan with asparagus, arrange shrimp in single layer on other side. Roast 7 minutes or until shrimp just turn opaque throughout.

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